William L Hunt wrote:
>  Does anyone (Edser?) think that self-determination of caste is NOT
> occurring in the Melopine stingless bees?
> 
Nothing you wrote seems to rule out maternal effects - i.e. it's the 
queen who's determining caste.  You can then explain the excess females 
as bet-hedging, as their caste is determined some time before hatching.

Just an alternative hypothesis.

Bob

>  I will explain further.
>  Self-determination of caste means there is an inherited
> genetic(allelic) difference between sister larva and because of this
> difference one follows a developmental pathway to become a sterile
> worker and the other to become a (potential) fertile queen. There
> should be an observable genetic difference in some alleles between the
> two.
>  In all higher eusocial insects except one, the caste
> (worker/reproductive) of the larva is determined, not by the larva
> herself, but by the workers usually by the amount or type of food
> given the larva. The exception is the Melopine stingless bees. In
> Melopona all cells are the same size, provisioned with identical
> amounts of food, and after the egg is laid the cell is capped. There
> is no further contact with the developing larva until it emerges as a
> fully formed worker or queen. It would seem that self-determination of
> caste is occurring. Melopona is among those bees that reproduce only
> by hive swarming (fission) and only need a new queen when swarming
> (maybe once or twice a season). Other hive swarming bees produce very
> few new queens but in Melopona as many as 25% of females may emerge as
> queens. They are all killed immediately by the workers (unless the
> hive is in the process of swarming when it would keep one). What a
> waste! The inefficiency of the Melopona hive producing all these
> queens just to immediately kill them is striking. If the workers
> controlled/determined the larva caste, they would never overproduce
> unneeded new queens.  Again it seems clear that self-determination of
> caste is occurring in Melopona.
>  I should note that as far as I know no lab has looked or is currently
> looking for the genetic difference between worker and queen in
> Melopona. If self-determination of caste is occurring there must be a
> genetic difference and I am quite curious what it actually is.
> Possible allelic mechanisms have been proposed (Kerr 1950).
>  I ask again if anyone thinks self-determination of caste is NOT
> occurring in the Melopine stingless bees?
> 
>  William L Hunt
>  
> 


-- 
Bob O'Hara

Rolf Nevanlinna Institute
P.O. Box 4 (Yliopistonkatu 5)
FIN-00014 University of Helsinki
Finland
Telephone: +358-9-191 23743
Mobile: +358 50 599 0540
Fax:  +358-9-191 22 779
WWW:  http://www.RNI.Helsinki.FI/~boh/
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